This is not floaters or any kind of ocular phenomenon I’ve searched. This is something different from everything else I’ve read about vision. I have floaters and stuff like that, but this bears no resemblance. I’ve been observing it for years.
On occasion I see a tiny pinprick of a black dot, surrounded by a thin bright halo. The halo is usually light green, but may be pink or white. It usually appears peripherally, though sometimes centrally. It lasts for only a few seconds. It drifts a little before it vanishes. I can see these dots with my eyes closed as well as open. With eyes closed, the black stands out against the general gray background.
No other changes have occurred to my vision. I don’t think this can be intraocular. I suspect the visual cortex. Maybe it’s a single cell in the visual cortex blowing a gasket. The hole only lasts a few seconds because the other cells fill in for the missing one. Or what?
I’ve observed something similar, though not particularly often, maybe once every month or two.
If you really pay attention, you can actually perceive a lot of small anomalies in your perception of vision that your brain usually just ignores. Since these are impossible to detect or characterize outside of your own perception, it seems to me that only the most obvious ones are documented in medical literature.
I am a pilot and about 6 years ago I was going through a period of very high emotional stress, and started noticing these sorts of things more often. Since vision is critical for flying I went to an ophthalmologist, who referred me to a retina specialist, who performed a bunch of expensive tests and found absolutely nothing of note. She also made a polite remark that this sort of hypochondria is common among pilots, who spend a lot of time staring at uniform blue skies and noticing any imperfections.
Gradually these went away, roughly as my personal stress diminished. I do still occasionally see small things like you describe, but they’ve never increased in severity and don’t seem to indicate any longer-running problem.
I don’t have a factual answer to what it might be, but if it only happens every month or two and doesn’t bother you, I wouldn’t worry about it unless it starts happening more often or becomes genuinely bothersome.
However, if you think it’s related to stress, I suggest a conversation with your PCP about it. They may refer you to an ophthalmologist, neurologist, or psychologist, depending on who would be best to help you figure it out.
I used to get floaters related to reading in poor lighting conditions. They went away for the most part, but sometimes when I’m reading a book, they’ll return and eventually disappear for a while.
I get (rarely) a different, brief in duration situation which is like a small blind spot that appears in the corner of my vision. Check this link for more information:
Doesn’t hurt to get regular eye exams. A lot of things can cause transient visual tchotchkes. But if things persist, affect your vision or field of vision, you see flashing lights or persistent haloes, or dozens (or even thousands) of floaters than you would get these checked out urgently.
I have many floaters of different kinds that I’ve accumulated over the years. Those are intraocular objects. What I’m talking about is not intraocular, not an object, but is probably a neural phenomenon, and my guess is something in the visual cortex.
It’s also distinct from the flying sparks that are seen when bearing down. There are many of those, they move quickly, and they vanish quickly. They are all brightness, whereas my phenomenon is matte black, lasts for several seconds, drifts slowly, and only occurs one at a time, at unpredictable intervals. It doesn’t match any of the descriptions of other visual anomalies I could find.
Although while trying to search about it, I learned of “blue sky entoptic” thingies. It’s the white blood cells in the blood vessels of your eyeballs. The visual cortex is programmed to automatically edit out the red of the blood in your eye’s blood vessels. So it doesn’t edit out the white and you can see them looking at a bright blue sky. They move in blood circulation like cars in traffic, but you can glimpse each one for only a split second before it moves out of view. I just thought that was pretty cool. But again, these are physical objects in the eye, not what I’m asking about.